Sound reproducing device



Aug. 23, 1932. s. L. PRICE 1,873,153

SOUND REPRODUC ING DEVI CE Filed Feb.VA 12, 1930 @/A i www HW PatentedAug. 23, 1932 *UNITED STATES,

' lSIDNEY LnoroLD rnIcE, or LONDON,V ENGLAND soivD E'PRODUCING DrivicnApplication led February 12, 1930, Serial lt\o."li27,8r55, and in GreatBritain February 20, 1929.AV

This invention relates to electromagnetic sound reproducing devices of.the type in which ai diaphragm, cone or other member is adapted to beoperated by anarniature arranged in a magnetic eld,'the invention beingparticularly suitable for loud-speakers for use'in connection with radiotelephony or for gramophone pick-ups. v

'It is an object of the invention to provide 1i) a device of thetypedescribed which, while being of simple-construction and inexpensiveto manufacture, and which will give substantially uniforml response toaA wide band of frequencies, aiiords animprovedV tone, volunie-andquality of reproduction.

The invention consists broadly in mounting, suspending or supporting thearmature directlyor indirectly upon resilient or flexi- -ble or othermeans adapted to aioidA comparatively" unrestricted freedom tovibrations/communicated according to the various 'speech modificationsof the energizingor controlling currents.V

The invention comprises supporting the armature of a device of the typedescribed from a' support by means comprising a-flexible or resilient orsuspensory member (or members)` which may be attached at one or bothends to thevsemi-rigid member! or other V support. y

The `armature may be directly supported by thel support, being attachedto the flexible or spring member or members, or 'the armature may befirmly attached to an arma* ture carrying member, prefer-ably oi' non'Fmagnetic material, which is itself connected l by theflexible or springmember' or members to-the semi-rigidmember or mainsupport.

The armature or intermediate member may be provided with a spindle forattachment to a diaphragm or cone of a loudspeaker, tele- Ehon'ereceiver or the like, andthe whole may e arranged in conjunction with amagnet system between which and' the armaturev ad- 4'5 justment may beeffected as is usual in the artf.-

According to OnecOnvenien'trmethod of lcarrying the invention intoeiiect the armature may be attached, asby' riVet-ing,screwin'g or thelike, to a4 semi-rigid armature carrying PATIENT @ma memberconsistinggior example, of a stout strip or bar of phosphor bronze orother nonmagnetic material, which member is hinged at or towards one endto a semi-rigid meinber or main support.V Attached adjacent to the otherend oit' the armaturel carrying member is the longer limb of a member inthe form of a springof roughly U-shape, while the shorter limb issecuredthrough an aperture to the main support or supporting member. e ng A .diaphragm spindle attached to the armature or armature Abar maypass through a further aperture provided for its accommo-V dation in thesemi-rigid member. The hinge may be formed by a pairoflateral extensionsonthe intermediate bar or member bentor otherwise formed'to embrace thesemi-rigid member or fitinto apertures inthe said'members, being furthersecured whe-reinecessaryl by soldering, brazing or otherwise.

In a modiiication of the above construction the` hinge is replaced by apivot or pin (or pins) on the .armature carrying-member, which pin mayconvenientlybe seated'in a .depression formed inthe semi-rigid memlberor .be otherwise secured by aid of the pin or pins. 'Alternatively, Vthepivot may be carried by th-e semifrigid support member and the seatingby the armature carrying memben- Y l f In the abovecase and thatforegoing, the armature may bepositioned centrallyof the `armaturecarrying bar or towards or away (from the spring connection.I l

VAcacordingjto` another arrangement, vthe armature carryingmembercarrying the armature-andspindle as indicated above, may

lbe provided with resilient extensions at its extremities for attachmentto the semi-rigid member. Such extensions may be in the form of stripsof the material of the member not completely detached therefrom, or

separate piecesv may be soldered, riveted or v otherwise attached to themember. The extensions may be parallel to each other and, Vwhere themember is rectangular, may be Aattached at diagonally opposite or atadjacent", corners of the rectangle. The extensions may make anydesirable angle with the .p longitudinal edges ofthe armature carryingor intermediate member, such as an mediatemember may be equallyv appliedto verse edges. Vhere the extensions are arranged at adjacent cornersthe extensions are preferably, maintained in the i same straight line,and the armatureis preferably arranged on the member so that the centreof mass of the combination lie'sapproxi-l mately on this line. H

According to another form a plurality of y resilient extensions may beprovided' at Veach end of the armature carryingor intermediate.

member for attachment'to the semi-rigid member. YIn the case of arectangular member a resilient extension may be arranged at each corner,preferably extending longitudinally, or a single extension or pin may bearranged atthe vmid points of the ends of the bar or member;

Alternatively, the armature. carryingy or intermediate member carryingthe armature may be attached by a plurality of small leaf springs to thesemi-rigidv member; for example, a leaf or other spring may be attachedadjacent to or at the extremitiesof the intermediateimember. The leafsprings maybe replaced by U-shaped springs having one arm longer thantheother, the longer arm preferab'lypassing through an aperture in therigid member and being attached to the armature carrying or intermediatemember or'armature, the `shorter arm being rattached to the semi-rigidmember.V

The foregoing modes of resiliently supporting an armature carrying baror .interthe armature of theV device in which case the intermediatemember may be dispensed with and the 'armature resili-ently mounted froma semi-rigid member or support. In ythe accompanying drawing I haveillustrated several forms that the invention may assume. L f

Figure 1 shows an armature carrying or intermediate member carrying thearmature 'ands mounted on a semi-,rigid member. c Y Figure2 is a View ofanother arrangement. Figure 3 showsthe device in cross section arrangedin a loud-speaker unit.

' Figures 4to 7 show various formsthatthe suspension of the armaturecarrying or intermediate member may take as viewed from the` sidetowhich the armature is alixed.

Figure 8 shows another method of suspension.

v Like references indicate like parts throughout-'the figures.

Referring to Figure 1, 1l is a supporting member comprising a strip ofphosphor bronze, brass orl the like which is semirigid. It is providedwith holes 2 for affix- `ing to asupport and with holes 3 and 4f..Attached .to the strip 1 by means of a hinge .justment'being 5 and aspring 6 is an intermediate or armature carrying membery 7,substantially rigid and of non-magnetic material. The spring 6 isattached as by soldering, or riveting to the member 7 and themember 1 at.the points 8 and 9, respectively, and one limb of it passes through'thehole 3 which isv suliciently large toA allow free vmovementof.thevlimbof the spring.I Attached to member 7 byvany con'- Venientv means,suchV as brazing or riveting, is the armature 10, comprising a piece ofsoft iron. A rod 11 is also aixed to the intermediate member at a pointabout the centre of the armature, so as-toV pass through the hole 4,which is such as to afford clearance.

for uniinpeded movement of the rod. f' The end of the rod is shownthreaded-atm sothat attachment maybe made to a diaphragm cone Vor thelike.

In the arrangementshown in Figure 2 the intermediate or armaturesupporting member is dispensed with, the armature'itself being directlyattached to thespiing 6 and the hinge 5. In order that the moving systemmay not be unduly massive the armature isshaped soas to comprise a'portion of holes in and soldered to the member 1 sothat the hingingeffect is .affordedlby the resilience of the wire. In Figures 2 and 3 Ihave shown the wire passing through two' suitable holes v5a vand 5bv inthe armature andtwo corresponding holes in the memberl, one only, 1a, ofwhich is shown. The wire is then soldered inpposition.. Ak singlejwiremay of course replace the two lengths `of wire. Again the hinge may takethe form of small p11()v rods attached firmly to the membervf? ortheV i.armature and seating on lconvenient faces on the-member 1 .or-vice-fversa. TheVspring-'G may be of phosphor bronze, steel or othersuitable resilient material. d

In Figure 3 the device s hownin Figure 2 is villustrated in position-ina loud-speaker unit.y Screws 16 connect the memberl to the casing 17 ofthe unit which is provided with the usual permanent magnets` 2l and polekpieces 2O carrying coils 19. An arrangement for adjusting the distancebetween the pole pieces and the armature 10 is' provided, ad-

made by the knurled headed screw 22.-

In Figuresa to 7 I have shown the armature v10 attached to` themember7'as .in the case of Figure 1. Instead, however-,of providing a hinge.'or pivot atrone end of the memberI provide resilient extensions atbothfends of. the member 7 lying in the plane of said member-.'ni'orndirect attachmentto struts or the like extending outwardly from the taceof themember l." The-,extensions 25,27, and 31 are ormedof the materialof the. member 7 .and are of such sectionaslto give thev requiredresiliency. The extensions 29 are pieces of suitabler wire or Vstrip*attached to the member 7 by soldering or otherwise. In the caseof Figure7 where thesup-k porting springs 3l are to one side of the centre of theintermediate member, the armature l0i s 4displaced in order that the`centre of gravity of the whole lies in the linesv of the springs. Theextensions are attachedto the member. l. At Athe points 8 I attach thelonger limb `of a spring 6 the other end of which is attached to a fixedmember or support as in the Vcase of Figures l to 3. The spring 6 isshown arranged at an angle to the length of the member 7 so as to avoidthe rod 11. V

In Figure 8 I have shown anotherl Way of i supporting the armature l()directly by Itwo springs 32 which are attached to the armature and thebar l in the same way as has been indicated Vin the Acaseof thearrangement shown in Figures 2 and 3. In this case also the hinge is notemployed. f. n In the above cases, vI may'arrange the spring 6 so thatit is below the supporting member, in which case the longer limb of thespring would be attached to the member 1 andthe shorter limb to themember 7 or the armature l0..V

It will be appreciated'that where I have shown the armature directlysuspended from the bar l, the alternative arrangement of suspending thearmature carrying or intermediate member with the armature attached ispossible and, similarly,.the methods shown of suspending the member 7may be applied to the armature l0. Also it will be understood that themember l may form part of an electromagnetic system and assume otherforms than that shown.

While the invention has been describedin connection with electromagneticdevices it maybe applied for a purely mechanical ar rangement such. asround in sound boxes of gramophones and the like, in which case theresilient mounting would be applied to the support of the needle andintermediate the latter and the diaphragm. F or example, the member lmay constitutepart of the sound boX or may be attached thereto. Thestylus bar may be resiliently supported as in the case of the armaturedescribed above, being either hinged adjacent to the end farthest fromthe `needle or stylus holder, or supported by a plurality of springs orresilient eX- tensions.l Y

, According to a modification I may attach the armature orarmature-carrying `member to. thevsupport by one ormorewires or the likeVstruts projecting:substantiallynormal `lyfthererom, tvvojbeing`arranged towards onefend ofthe armaturesor1armaturecarry memberV andone towards theo-pposite end' thereot and preferably equidistant formthe other two. Imay lmake the supportof a resilient bar, frame or thelike, attached .at itsY ends to a` substantially rigid support-1 ingstructure.` Again, I `may increasethe llength of 'thewires or struts4 sothat they i become more resilient and so'render'unneces-r sary anyfurther` resilient member. Where,

asin thelatter case, I rely `on the-resiliency -ofrthe wires or struts,`I `may arrange, them at anangle to Vthe plane oi"- the armaturey orarmatureecarrying member so that the resilient eect is obtained byslight bending of the wires. r i i y Where in the speciiication andclaims I have used the term U-shaped spring or 9U-,

stoodI include any spring having parallel limbs, whether the limbs areoined by: a ysimple bend or one or more coils of the material. t .Y

Having now described my inventiomwhat I claim as new and desire tosecure by Letf ters Patentisz* Y y 1.7,The method of`supportingthemagnetic armature of an electromagnetic'device adapted foruse in the reproduction of sound, which compris-es suspending thearmature having connected thereto a: diaphragm actuating stylus fromasemi-rigid member in the form of a reed by means Vcomprising-at least'one rey' 4silient member, whereby to afford to the ar-` freedom shapedresilient member itis to be underiis porting member from which amagnetic" ary mature is suspended and spaced and adiaphragm actuatingstylus connected to thejarmature but having no positivefconnection iwith the supportingmember. l

4l. In anelectromagnetic device for use in the reproduction of sound, asemi-rigidsupporting member in the form of a reed, from which a magneticarmature is suspended Vand spaced and a diaphragm actuating stylus 4connected to the armature but having no positive connection withthesupporting member- 5. In an-electromagnetic device for uselin thereproduction of sound,l a magnetic armature, a semi-rigid supportingmemberfinthe formof a reedfrom'which an armature carrying member issuspended and spaced and a diaphragm actuating stylus connected to thearmature having no positive connection with the supporting member. Y

Y V6.J In an electromagnetic device adapted for usein the reproductionof sound, a vibratory member including a magneticarmature,

a diaphragm actuating stylus connected to the vibratory member, asemi-rigid supporting member in the form of a reed and at least oneresilient member attaching the vibratory Y member to the semi-rigidsupporting member s so as toaiford to the vibratory member comparativelyunrestricted Vfreedom to vibrate. -7. In an electromagnetic deviceadapted for use in the reproductionl of sound, a vibratory memberincluding a magnetic armature,

a magnet system arranged adjacent the armaber comparatively unrestrictedfreedom to vivbrate.

8. In an electromagnetic `device adapted for use in the reproduction ofsound, a vibratory member including a magnetic armature,

a diaphragm actuating stylus connected to the vibratory member, asemi-rigid supporting member in the vform of a reed, a hinge adjacenttoone end of the vibratorymembei` connecting said vibratory member to Vthesemi-rigid supporting member and a resilient connection between thevibratory member and the semi-rigid supporting member arranged adjacentto the other end of said vibratory member.

9. In an electromagnetic device adapted for use in the reproduction ofsound, a vibratory member including a magnetic armature, anelectromagnet system arranged adjacent the armature, a diaphragmactuating stylusV connected to the vibratory member, a semi-rigidsupporting member in the -lform of a reed, a hinge adjacent to one endof the vibratory member connecting said vibratory member to thesemi-rigid supportingmember and a resilient connection between theVibratory member and the semi-rigid supporting member arranged adjacentto the other end of said vibratory member.

10. In an electromagneticy device adapted for use in the reproductionyof sound, a vibratory member including a magnetic armature, a diaphragmactuating styluscone nected to the vibratory member, a semi-rigidsupporting member in the form of a reed and a plurality of resilientsprings attaching the vibratory member to thesemirigid supportingmemberso as to afford tothe vibratory member comparatively unrestrictedfreedom to vibrate.

ill. In an electromagnetic device-adapted' foruse in thefr-eproductionofJsound, a. vi-

bratory member including a magnetic armature, a magnetsystem arrangedadjacent the armature, a diaphragmactuating stylus connected to thevibratory member,a semi-rigid supportingv member in the formnoi a reed sand a plurality of resilientsprings attaching the vibratorymember tothe'semi-rigidy supporting member so as .to afford to the vibratorymember comparatively'unrestricted Vfreedom yto vibrate.

12. Inan electromagnetic device yadapted for use in the reproduction ofsound, a vif bratory member including a magnetic armature, and anintermediate member carrying the armature, a magnet system arrangedadjacent the armature, a diaphragm actuating stylus connected to thevibratory member, a semirigid supporting member inv thepfolrm of a reedyand resilient extensions on said intermediate member, attaching'thevibratory member to the semi-rigid supporting member so as to aiiord tothe vibratory mem-- ber comparatively unrestricted. freedom to vibrate.

13. In an electromagnetic device *adaptedA ber comparativelyunrestricted lfreedom to vibrate. y

14. In an electromagnetic device for reproducingsound, means forproducing a magnetic held, means for causingvariations in said magneticfield, a semi-rigid support in the. form of Ya reed, a vibratory membercomprising a magnetic armature and at least one resilient connectionbetween `said semirigid support and the'vibratory member supporting thevibratorymember withthe armature .in the magnetic field. v

15. kIn an electromagnetic device -or re-k producing sound, means forproducing a magnetic field, means for causing variations in saidmagnetic field, a vibratory member comprising a magneticy armature, adiaphragm actuating stylus attached to the vibratory member, asemi-rigid support in the form of a reed from which the vibratory memberis suspended and atleast one U-V shaped resilient ,connection betweensaid semi-rigid support and the vibratory member supporting thevibratory member with the armature in the magnetic field. Y

16. In an electromagnetic device for reproducing sound, means forproducing a magnetic field, meansy for causing variations

